Adenosine potentiates the therapeutic effects of neural stem cells expressing cytosine deaminase against metastatic brain tumors.

Tumor-tropic properties of neural stem cells (NSCs) provide a novel approach with which to deliver targeting therapeutic genes to brain tumors. Previously, we developed a therapeutic strategy against metastatic brain tumors using a human NSC line (F3) expressing cytosine deaminase (F3.CD). F3.CD converts systemically administered 5-fluorocytosine (5-FC), a blood-brain barrier permeable nontoxic prodrug, into the anticancer agent 5-fluorouracil (5-FU). In this study, we potentiated a therapeutic strategy of treatment with nucleosides in order to chemically facilitate the endogenous conversion of 5-FU to its toxic metabolite 5-FU ribonucleoside (5-FUR). In vitro, 5-FUR showed superior cytotoxic activity against MDA-MB-435 cancer cells when compared to 5-FU. Although adenosine had little cytotoxic activity, the addition of adenosine significantly potentiated the in vitro cytotoxicity of 5-FU. When MDA-MB­435 cells were co-cultured with F3.CD cells, F3.CD cells and 5-FC inhibited the growth of MDA-MB-435 cells more significantly in the presence of adenosine. Facilitated 5-FUR production by F3.CD was confirmed by an HPLC analysis of the conditioned media derived from F3.CD cells treated with 5-FC and adenosine. In vivo systemic adenosine treatment also significantly potentiated the therapeutic effects of F3.CD cells and 5-FC in an MDA-MB-435 metastatic brain tumor model. Simple adenosine addition improved the antitumor activity of the NSCs carrying the therapeutic gene. Our results demonstrated an increased therapeutic potential, and thereby, clinical applicability of NSC-based gene therapy.

Chemo-enzymatic saccharification and bioethanol fermentation of lipid-extracted residual biomass of the microalga, Dunaliella tertiolecta.

Chemo-enzymatic saccharification and bioethanol fermentation of the residual biomass of Dunaliella tertiolecta after lipid extraction for biodiesel production were investigated. HCl-catalyzed saccharification of the residual biomass at 121 °C for 15 min produced reducing sugars with a yield of 29.5% (w/w) based on the residual biomass dry weight. Various enzymes were evaluated for their ability to saccharify the residual biomass. Enzymatic saccharification using AMG 300 L produced 21.0 mg/mL of reducing sugar with a yield of 42.0% (w/w) based on the residual biomass at pH 5.5 and 55 °C. Bioethanol was produced from the enzymatic saccharification products without additional pretreatment by Saccharomyces cerevisiae with yields of 0.14 g ethanol/g residual biomass and 0.44 g ethanol/g glucose produced from the residual biomass. The waste residual biomass generated during microalgal biodiesel production could be used for the production of bioethanol to improve the economic feasibility of microalgal biorefinery.

Characterization of a renewable extracellular polysaccharide from defatted microalgae Dunaliella tertiolecta.

Extracellular polysaccharide (EPS) was isolated from defatted micro-algae Dunaliela tertiolecta and defined as linear (1→4)-α-D-glucan based on monosaccharide composition, enzymatic and spectroscopic analyses. Optimization and characterization of acidic and enzymatic hydrolyses of EPS have been performed for its potential use as a renewable biorefinery material. The hydrolytic methods were improved to assess the effect of substrate specificity, reaction time, pH, ionic strength and temperature on efficiency of glucose production. EPS was effectively converted into glucose within one-step enzymatic or acidic hydrolysis under optimized conditions. Over 90% recovery of glucose was achieved for both hydrolytic approaches. High potential production of EPS and high yield conversion of this substrate to glucose may allow further exploration of microalga D. tertiolecta as a potential biomass producer for biotechnological and industrial exploitation of bioethanol.

Identification of prognostic biomarkers for glioblastomas using protein expression profiling.

A set of proteins reflecting the prognosis of patients have clinical significance since they could be utilized as predictive biomarkers and/or potential therapeutic targets. With the aim of finding novel diagnostic and prognostic markers for glioblastoma (GBM), a tissue microarray (TMA) library consisting of 62 GBMs and 28 GBM-associated normal spots was constructed. Immunohistochemistry against 78 GBM-associated proteins was performed. Expression levels of each protein for each patient were analyzed using an image analysis program and converted to H-score [summation of the intensity grade of staining (0-3) multiplied by the percentage of positive cells corresponding to each grade]. Based on H-score and hierarchical clustering methods, we divided the GBMs into two groups (n=19 and 37) that had significantly different survival lengths (p<0.05). In the two groups, expression of nine proteins (survivin, cyclin E, DCC, TGF-ß, CDC25B, histone H1, p-EGFR, p-VEGFR2/3, p16) was significantly changed (q<0.05). Prognosis-predicting potential of these proteins were validated with another independent library of 82 GBM TMAs and a public GBM DNA microarray dataset. In addition, we determined 32 aberrant or mislocalized subcellular protein expression patterns in GBMs compared with relatively normal brain tissues, which could be useful for diagnostic biomarkers of GBM. We therefore suggest that these proteins can be used as predictive biomarkers and/or potential therapeutic targets for GBM.

Genetically engineered human neural stem cells with rabbit carboxyl esterase can target brain metastasis from breast cancer.

Neural stem cells (NSCs) led to the development of a novel strategy for delivering therapeutic genes to tumors. NSCs expressing rabbit carboxyl esterase (F3.CE), which activates CPT-11, significantly inhibited the growth of MDA-MB-435 cells in the presence of CPT-11. F3.CE cells migrated selectively into the brain metastases located in the opposite hemisphere. The treatment also significantly decreased tumor volume in immune-deficient mice bearing MDA-MB-435 tumors when F3.CE cells were transplanted into the contralateral hemisphere. The survival rate was significantly prolonged with the treatment with F3.CE and CPT-11. This strategy may be considered as an effective treatment regimen for brain metastases.

Combined effects of probiotic fermentation and high-pressure extraction on the antioxidant, antimicrobial, and antimutagenic activities of deodeok (Codonopsis lanceolata).

This study was designed to evaluate the combined effects of probiotic fermentation and high-pressure extraction (HPE) on the functional properties of Codonopsis lanceolata. The ground C. lanceolata samples were anaerobically fermented with Lactobacillus acidophilus ADH, Bifidobacterium longum B6, Lactobacillus rhamnosus GG, or Lactobacillus paracasei at 37 degrees C for 10 days and subjected to 500 MPa at 50 degrees C for 30 min. The extraction yields of C. lanceolata samples were noticeably increased to 29-32% by HPE. The B. longum-fermented C. lanceolata samples extracted by high pressure (BLF-HPE) exhibited the highest antimicrobial activity (MIC < 14 mg/mL) against Listeria monocytogenes, Staphylococcus aureus, Shigella boydii, and Salmonella typhimurium. The nonfermented C. lanceolata samples extracted with high pressure (NF-HPE) had the highest total phenolic content (13.3 mg of GAE/g). The lowest effective concentrations (EC(50) and EC(0.5)) were 4.55 and 1.76 mg/mL, respectively, for NF-HPE extracts, indicating its highest antioxidant activity. The BLF-HPE and L. rhamnosus-fermented C. lanceolata samples extracted by high pressure (LRF-HPE) exhibited the highest antimutagenic activities in S. typhimurium TA 100, which were 82 and 83% inhibition, respectively. The use of probiotic fermentation and HPE can produce more biologically active compounds in C. lanceolata than the conventional solvent extraction method. The results provide pharmaceutically useful information for improving biological properties and an approach to drug discovery.